Engine cooling system

ABSTRACT

An engine cooling system may include a cylinder head arranged on a cylinder block, a main thermostat arranged to control a coolant to be supplied to the cylinder block and the cylinder head according to a coolant temperature, and a coolant control valve unit having a first inlet for introduction of a block coolant which is the coolant supplied to and passed through the cylinder block and a second inlet for introduction of a head coolant which is the coolant supplied to and passed through the cylinder head, and controlling flows of the block coolant and the head coolant separately, as one unit.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority of Korean Patent Application Number 10-2013-0167834 filed on Dec. 30, 2013, the entire contents of which application are incorporated herein for all purposes by this reference.

BACKGROUND OF INVENTION

1. Field of Invention

The present invention relates to an engine cooling system in which coolant flowing to a cylinder head is separated from the coolant flowing to a cylinder block for fast warming up, and the coolant is controlled separately for maintaining a temperature of the cylinder block high to reduce friction energy and fuel consumption.

2. Description of Related Art

The engine generates a torque by burning fuel, and exhausts the remainder in thermal energy. Particularly, coolant absorbs heat while circulating the engine, a heater and a radiator and dissipates the heat to an outside of the engine.

If a coolant temperature of the engine is low to elevate oil viscosity, it is a trend that friction force and fuel consumption increases and a temperature of exhaust gas rises slowly resulting to prolong a time period of catalyst activation to make a quality of the exhaust gas poor. Along with this, there is a trend that a time period for bringing a heater function to a normal level takes a long time to make occupants and a driver to feel cold.

If the coolant temperature of the engine is excessive, knocking takes place, and, if ignition timing is adjusted for suppressing the knocking, performance is liable to become poor. And, if a lubrication oil temperature is excessive, a lubrication action is liable to become poor.

In the meantime, research is underway, in which the coolant flowing to the cylinder block and the coolant flowing to the cylinder head is controlled separately to maintain a temperature of the cylinder block comparatively high, for improving fuel efficiency and to maintain a temperature of the cylinder head comparatively low for reducing the friction energy.

The information disclosed in this Background section is only for enhancement of understanding of the general background of the invention and should not be taken as an acknowledgement or any form of suggestion that this information forms the prior art already known to a person skilled in the art.

SUMMARY OF INVENTION

The present invention is directed to provide an engine cooling system in which coolant flowing to the cylinder block and coolant flowing to the cylinder head is controlled separately to maintain a temperature of the cylinder block comparatively high for improving fuel efficiency and to maintain a temperature of the cylinder head comparatively low for reducing friction energy, and the coolant temperature is elevated quickly after starting the engine for minimizing a friction loss at an initial starting of the engine.

Thus, according to various aspects of the present invention, an engine cooling system may include a cylinder head arranged on a cylinder block, a main thermostat arranged to control a coolant to be supplied to the cylinder block and the cylinder head according to a coolant temperature, and a coolant control valve unit having a first inlet for introduction of a block coolant which is the coolant supplied to and passed through the cylinder block and a second inlet for introduction of a head coolant which is the coolant supplied to and passed through the cylinder head, and controlling flows of the block coolant and the head coolant separately.

The engine cooling system may further includes a control unit for controlling a coolant valve, and the coolant control valve unit may include the coolant valve operated by an actuator for controlling the head coolant, and a block thermostat operated according to a temperature of the block coolant for controlling the block coolant. The coolant control valve unit may have outlets for supplying the coolant passed through the coolant valve to a heater, an oil cooler, and/or a radiator, respectively.

The coolant passed through the main thermostat may be pumped by a coolant pump for supplying the coolant to the cylinder block and the cylinder head. The engine cooling system may be opened/closed by the coolant temperature flowing to the main thermostat.

The coolant valve may be opened or closed by the control unit according to a temperature of the head coolant. The block thermostat may be opened or closed by a temperature of the block coolant.

If the coolant valve is opened in a state the main thermostat is closed, the coolant may circulate to the cylinder head through the heater, the oil cooler, and the coolant pump. If the coolant valve is opened in a state the main thermostat is opened, the coolant may circulate to the cylinder head through the heater, the oil cooler, the radiator, and the coolant pump. If the coolant valve is opened in a state the block thermostat and the main thermostat are opened, the coolant may circulate to the cylinder head through the heater, the oil cooler, the radiator, and the coolant pump.

In the present invention, the coolant valve of the coolant control valve is operated according to a temperature of the head coolant passing through the cylinder head to block a coolant flow to an outside of the engine at an initial stage of engine starting for rapid elevation of the engine coolant temperature to reduce a low temperature period compared to an engine having no device of the present invention.

By controlling the cylinder head to be at a comparatively low temperature, and making the block thermostat of the coolant control valve unit to be operated by a temperature of the block coolant, the cylinder block can be controlled to be at a comparatively low temperature.

Along with this, the main thermostat may be operated according to an overall coolant temperature, for making the coolant to circulate through the radiator, selectively.

The methods and apparatuses of the present invention have other features and advantages which will be apparent from or are set forth in more detail in the accompanying drawings, which are incorporated herein, and the following Detailed Description, which together serve to explain certain principles of the present invention.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a block diagram illustrating an exemplary engine cooling system according to the present invention.

FIG. 2 is a plan view schematically illustrating a coolant control valve unit in an exemplary engine cooling system according to the present invention.

FIG. 3 is a block diagram illustrating an exemplary engine cooling system according to the present invention, showing a coolant flow at an initial starting of the engine.

FIG. 4 is a block diagram illustrating an exemplary engine cooling system according to the present invention, showing a coolant flow according to a coolant temperature flowing to a cylinder head.

FIG. 5 is a block diagram illustrating an exemplary engine cooling system according to the present invention, showing a coolant flow according to a coolant temperature flowing to a main thermostat.

FIG. 6 is a block diagram illustrating an exemplary engine cooling system according to the present invention, showing a coolant flow according to a coolant temperature flowing to a cylinder block.

DETAILED DESCRIPTION

Reference will now be made in detail to various embodiments of the present invention(s), examples of which are illustrated in the accompanying drawings and described below. While the invention(s) will be described in conjunction with exemplary embodiments, it will be understood that present description is not intended to limit the invention(s) to those exemplary embodiments. On the contrary, the invention(s) is/are intended to cover not only the exemplary embodiments, but also various alternatives, modifications, equivalents and other embodiments, which may be included within the spirit and scope of the invention as defined by the appended claims.

FIG. 1 illustrates a block diagram of an engine cooling system according to various embodiments of the present invention. Referring to FIG. 1, the engine cooling system includes a cylinder head 100, a cylinder block 110, a coolant control valve unit 170, a heater 130, an oil cooler 160, a coolant pump 140, a main thermostat 150, a radiator 120, and a control unit 99.

The coolant circulates through the coolant pump 140, the cylinder head 100, the cylinder block 110, the coolant control valve unit 170, the heater 130, the oil cooler 160, the radiator 120, and the main thermostat 150.

In more detail, the coolant pumped by the coolant pump 140 flows to the cylinder head 100 and the cylinder block 110 separately controlled by the coolant control valve unit 170.

And, the coolant supplied to the coolant control valve unit 170 is supplied to the heater 130, the oil cooler 160, and the radiator 120 depending on conditions, separately. In this case, if the main thermostat 150 is opened, the coolant circulates through the radiator 120.

Along with this, the coolant control valve unit 170 has a structure in which the coolant control valve unit 170 controls head coolant circulating through the cylinder head 100 and block coolant circulating through the cylinder block 110, separately.

The control unit 99 senses a temperature of the head coolant circulating through the cylinder head 100 with a sensor, and opens a coolant valve 210 according to the temperature of the head coolant sensed thus for circulating the coolant to the cylinder head 100.

FIG. 2 illustrates a plan view of a coolant control valve unit provided to engine cooling system according to various embodiments of the present invention, schematically. Referring to FIG. 2, the coolant control valve unit 170 includes a housing 250, a first inlet 202, a second inlet 204, an actuator 220, a solenoid valve 230, and a block thermostat 200, and the housing 250 has outlets connected to the heater 130, the radiator 120, and the oil cooler 160, respectively.

The first inlet 202 has the head coolant passed through the cylinder head 100 supplied thereto, and the second inlet 204 has the block coolant passed through the cylinder block 110 supplied thereto.

The head coolant being supplied to the first inlet 202 is controlled by the coolant valve 210, to circulate through the heater 130, the oil cooler 160, and the radiator 120. In this case, if the main thermostat 150 opens, the coolant circulates through the radiator 120.

The block coolant being supplied to the second inlet 204 is controlled by a block thermostat 200, to circulate through the heater 130, the oil cooler 160, and the radiator 120. In this case, if the main thermostat 150 opens, the coolant circulates through the radiator 120.

The coolant valve 210 is operated by the actuator 220, the actuator 220 is operated by the solenoid valve 230, and the solenoid valve 230 is controlled by the control unit 99.

As described before, the control unit 99 senses the temperature of the head coolant with a sensor, and opens the coolant valve 210 according to the temperature of the head coolant sensed thus for maintaining the temperature of the cylinder head 100 at a comparatively low temperature.

In various embodiments of the present invention, the block thermostat 200 is of a type operated by the temperature of the block coolant, and the main thermostat 150 is of a type operated by the temperature of the coolant passing through the main thermostat 150.

FIG. 3 illustrates a block diagram of an engine cooling system according to various embodiments of the present invention, showing a coolant flow at an initial stage of starting. Referring to FIG. 3, at the initial stage of starting, the main thermostat 150 is closed and both of the coolant valve 210 and the block thermostat 200 of the coolant control valve unit 170 are closed. Therefore, the coolant does not circulate or flow only in the cylinder head 100 and the cylinder block 110.

In various embodiments of the present invention, the coolant pump 140, being of an electric type, may or may not be operated by the control unit 99.

FIG. 4 illustrates a block diagram of an engine cooling system according to various embodiments of the present invention, showing a coolant flow according to a coolant temperature flowing to a cylinder head. Referring to FIG. 4, if the temperature of the head coolant passing through the cylinder head 100 is higher than a preset value, the control unit 99 opens the coolant valve 210 of the coolant control valve unit 170 to make the coolant to flow through the cylinder head 100, and the coolant being supplied to the coolant control valve unit 170 circulates through the heater 130, the oil cooler 160, the coolant pump 140 and the cylinder head 100.

The block thermostat 200 of the coolant control valve unit 170 maintains a closed state according to the temperature of the block coolant, to make the temperature of the block coolant to be maintained at a comparatively high temperature. In this case, the main thermostat 150 is in a closed state in which the coolant does not circulate through the radiator 120.

According to this, since the cylinder block 110 and the cylinder head 100 are warmed up quickly, and the temperature of the cylinder block 110 is maintained comparatively high, the viscosity of the lubricant drops, and the combustion efficiency becomes high, to improve overall combustion efficiency of the internal combustion engine and to increase overall output.

FIG. 5 illustrates a block diagram of an engine cooling system according to various embodiments of the present invention, showing a coolant flow according to a coolant temperature flowing to a main thermostat. FIG. 5 illustrates a state in which the coolant valve 210 of the coolant control valve unit 170 is opened, the block thermostat 200 is closed, and the main thermostat 150 is opened.

Therefore, the coolant circulates through the cylinder head 100, the coolant control valve unit 170, the heater 130, the oil cooler 160, the radiator 120, the main thermostat 150 and the coolant pump 140.

However, since the block thermostat 200 is in a closed state, the cylinder block 110 is controlled to be at a comparatively high temperature, to drop the viscosity of the lubricant, and to make the combustion efficiency high, thereby improving the overall combustion efficiency of the internal combustion engine and increasing overall output.

FIG. 6 illustrates a block diagram of an engine cooling system according to various embodiments of the present invention, showing a coolant flow according to a coolant temperature flowing to a cylinder block. FIG. 6 illustrates a state in which the coolant valve 210 of the coolant control valve unit 170 is opened, the block thermostat 200 is opened, and the main thermostat 150 is opened.

Therefore, the coolant circulates through the cylinder head 100, the cylinder block 110, the coolant control valve unit 170, the heater 130, the oil cooler 160, the radiator 120, the main thermostat 150 and the coolant pump 140.

However, since the block thermostat 200 is in an opened state, the coolant circulates through the radiator 120 such that the temperature of the block coolant passing through the cylinder block 110 does not exceed a limiting point.

The foregoing descriptions of specific exemplary embodiments of the present invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The exemplary embodiments were chosen and described in order to explain certain principles of the invention and their practical application, to thereby enable others skilled in the art to make and utilize various exemplary embodiments of the present invention, as well as various alternatives and modifications thereof. It is intended that the scope of the invention be defined by the Claims appended hereto and their equivalents. 

What is claimed is:
 1. An engine cooling system comprising: a cylinder head arranged on a cylinder block; a main thermostat arranged to control a coolant to be supplied to the cylinder block and the cylinder head according to a coolant temperature; and a coolant control valve unit having a first inlet for introduction of a block coolant which is the coolant supplied to and passed through the cylinder block and a second inlet for introduction of a head coolant which is the coolant supplied to and passed through the cylinder head, and controlling flows of the block coolant and the head coolant separately, as one unit.
 2. The engine cooling system of claim 1, further comprising a control unit for controlling a coolant valve, wherein the coolant control valve unit includes: the coolant valve operated by an actuator for controlling the head coolant, and a block thermostat operated according to a temperature of the block coolant for controlling the block coolant.
 3. The engine cooling system of claim 2, wherein the coolant control valve unit has outlets for supplying the coolant passed through the coolant valve to a heater, an oil cooler, and/or a radiator, respectively.
 4. The engine cooling system of claim 2, wherein the coolant passed through the main thermostat is pumped by a coolant pump for supplying the coolant to the cylinder block and the cylinder head.
 5. The engine cooling system of claim 2, wherein the system is opened/closed by the coolant temperature flowing to the main thermostat.
 6. The engine cooling system of claim 2, wherein the coolant valve is opened or closed by the control unit according to a temperature of the head coolant.
 7. The engine cooling system of claim 2, wherein the block thermostat is opened or closed by the temperature of the block coolant.
 8. The engine cooling system of claim 2, wherein if the coolant valve is opened in a state the main thermostat is closed, the coolant circulates to the cylinder head through a heater, an oil cooler, and a coolant pump.
 9. The engine cooling system of claim 2, wherein if the coolant valve is opened in a state the main thermostat is opened, the coolant circulates to the cylinder head through a heater, an oil cooler, a radiator, and a coolant pump.
 10. The engine cooling system of claim 2, wherein if the coolant valve is opened in a state the block thermostat and the main thermostat are opened, the coolant circulates to the cylinder head through a heater, an oil cooler, a radiator, and a coolant pump. 